Exercise provides many benefits for the body and mind. In some rare cases, exercise can cause an excess of the neurotransmitter dopamine. Dopamine is a catecholamine, along with serotonin, epinephrine and norepinephrine. This group of neurotransmitters functions in response to physical and emotional stress and has a direct impact on metabolic pathways. Dopamine is involved in the functions of the heart, kidneys, nerves and muscles. Its release in the central nervous system is necessary for movement and control of the body and the pleasure, pain and reward emotions. Exercise influences this balance by affecting the storage and release of dopamine.
Symptoms
Excessive dopamine can lead to an overstimulation of the risk-reward emotion and behavior. Extreme amounts of dopamine are linked to more serious conditions such as Tourette's syndrome and Tardive dyskinesia. Other symptoms include anxiety, paranoia, lack of self-control, addiction and exercise overtraining. The reward emotion derived from excessive dopamine release from exercise overtraining can become a cyclic behavior.
Causes
Exercise directly affects the release and storage of neurotransmitters, including dopamine. Many activities stimulate a normal release of dopamine, including walking and massage therapy. Excessive exercise over a long period of time causes a greater amount of dopamine to be released than normal physical activity. Excessive dopamine is more likely to occur in people who have other health issues such as adrenal dysfunction, history of addictive behavior and those taking medications such as L-dopa.
Prevention
Dopamine binds to receptors immediately upon release, resulting in the reward behavior being learned quickly. To minimize the impact of excessive dopamine, eat a well-balanced diet that includes foods rich in calcium, copper, vitamin B6 and theanine. Care should be taken when using nutritional supplements and medications such as monoamine oxidase inhibitors and 5HTP to ensure they do not interact.
Tests and Treatments
There is no single test to confirm the diagnosis of conditions such as Tardive dyskinesia or Tourette's syndrome. A combination of multiple physical examinations and neuropsychological evaluations may be necessary. For treatments of these and other conditions related to excessive dopamine levels, receptor blockers and agonists are considered to restore normal levels. Medications such as tetrabenzine have had some success.
References
- "Journal of Nuclear Medicine"; PET Studies of the Effects of Aerobic Exercise on Human Striatal Dopamine Release"; Gene-Jack Wang, et al.; August 2000
- "European Journal of Applied Physiology"; Modulatory Catecholamine-Synthesizing Enzymes in Adrenal Medulla and Stellate Ganglia by Treadmill Exercise of Stressed Rats; l. Gavrilovic, et al.; June 2011
